package cn.com.haopy.yue.ai.core.utils;

import org.springframework.util.StringUtils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

/**
 * @author keel
 * @date 2023/12/8
 */
public class AESUtil {

    //获取Cipher对象的算法
    private static final String ALGORITHMSTR = "AES/ECB/PKCS5Padding";

    /**
     * base 64 encode
     * @param bytes 待编码的byte[]
     * @return 编码后的base 64 code
     */
    public static String base64Encode(byte[] bytes){
        return Base64.getEncoder().encodeToString(bytes);
    }

    /**
     * base 64 decode
     * @param base64Code 待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception
     */
    public static byte[] base64Decode(String base64Code){
        return StringUtils.hasText(base64Code) ? Base64.getDecoder().decode(base64Code) : null;
    }

    /**
     * 生成AES秘钥
     */
    public static String generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
        keyGenerator.init(128);
        SecretKey secretKey = keyGenerator.generateKey();
        return base64Encode(secretKey.getEncoded());
    }

    /**
     * AES加密
     * @param content 待加密的内容
     * @param encryptKey 加***
     * @return 加密后的byte[]
     * @throws Exception
     */
    public static byte[] encryptToBytes(String content, String encryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128);
        Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(encryptKey.getBytes(), "AES"));

        return cipher.doFinal(content.getBytes(StandardCharsets.UTF_8));
    }


    /**
     * AES加密为base 64 code
     * @param content 待加密的内容
     * @param encryptKey 加***
     * @return 加密后的base 64 code
     * @throws Exception
     */
    public static String encrypt(String content, String encryptKey) throws Exception {
        return base64Encode(encryptToBytes(content, encryptKey));
    }

    /**
     * AES解密
     * @param encryptBytes 待解密的byte[]
     * @param decryptKey 解***
     * @return 解密后的String
     * @throws Exception
     */
    public static String decryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128);

        Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(decryptKey.getBytes(), "AES"));
        byte[] decryptBytes = cipher.doFinal(encryptBytes);
        return new String(decryptBytes);
    }

    /**
     * 将base 64 code AES解密
     * @param encryptStr 待解密的base 64 code
     * @param decryptKey 解***
     * @return 解密后的string
     * @throws Exception
     */
    public static String decrypt(String encryptStr, String decryptKey) throws Exception {
        return StringUtils.hasText(encryptStr) ? decryptByBytes(base64Decode(encryptStr), decryptKey) : null;
    }
}
